4_l__-_Crystal_Springs_Construction_Sequence.pdf

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Table of Contents

1 Project Planning

1.1 Recommended Sequence of Restoration Projects

1.2 Permitting

1.3 Budgeting for Restoration Projects

2 Hydrologic Barriers

3 Construction Sequences For Proposed CMU Restoration Projects

3.1 Crystal Spring

3.1.1 Construction Timing

3.1.2 Pre-Construction

3.1.3 Construction

3.1.4 Post-Construction

3.2 Crystal Reservoir

3.3 Lower Kings Spring Outflow Channel

3.3.1 Construction Timing

3.3.2 Pre-Construction

3.3.3 Construction

3.3.4 Post-Construction

3.4 Forest Spring

3.4.1 Construction Timing

3.4.2 Pre-Construction

3.4.3 Construction

3.4.4 Post-Construction

3.5 Davis Spring

3.5.1 Construction Timing

3.5.2 Pre-Construction

3.5.3 Construction

3.5.4 Post-Construction

3.6 Bradford Springs (1 and 2)

3.6.1 Construction Timing

3.6.2 Pre-Construction

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3.6.3 Construction

3.6.4 Post-Construction

3.7 Tubbs Spring

3.7.1 Construction Timing

3.7.2 Pre-Construction

3.7.3 Construction

3.7.4 Post-Construction

4 Recommended Equipment

5 Measures Taken to Minimize Impact

5.1 Protection of Vegetation and Sensitive Species

5.2 Protection of Cultural Resources

5.3 Water Quality Control

5.3.1 Construction Planning

5.3.2 Construction Site Best Management Practices (BMPs)

5.4 Air Quality Control

6 Best Management Practices (BMPs)

6.1 Flagging and Wire Pin Flags

6.2 Marking Paint

6.3 Orange Construction Fence

6.4 Silt Fence

6.5 Fiber Rolls

6.6 Equipment and Materials Staging Areas

6.7 Contamination Prevention

6.8 Construction Access Roads

7 References

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1 PROJECT PLANNING

1.1 Recommended Sequence of Restoration Projects

Otis Bay, Inc. (OBEC) recommends the following sequence for implementation of spring and channel restoration projects in the Crystal Spring Management Unit (CMU) based on logistics related to construction and dewatering. Restoration projects in the CMU can be divided into two main groups:

Group 1: Crystal Spring and Crystal Reservoir. Restoration of Crystal Spring channel should occur before removal of Crystal Reservoir, so that the reservoir may be used as part of the Crystal Spring channel dewatering plan. After restoring the Crystal Spring channel, the source of inflow water to the reservoir will be removed, and the reservoir can be dewatered and restored to a natural drainage.

Group 2: Kings, Forest, Davis, Bradford and Tubbs Springs. Restoration of these springs can be organized to coordinate dewatering activity and efficient removal of outflow ditches. OBEC recommends that Lower Kings, Forest and Davis springs and channels be restored in progression from east to west for most efficient removal of the main ditch that currently carries outflow from these springs. OBEC recommends that restoration at Bradford Springs occur before Tubbs Spring, because the main outflow/dewatering ditch from Bradford Springs crosses the proposed restored alignment for Tubbs Spring and must be removed prior to construction of the restored Tubbs channel.

OBEC recommends that Group 1 projects (Crystal Spring and Crystal Reservoir) occur before the Group 2 projects. Outflow from several of the restored Group 2 springs (Bradford 1 and 2) will travel toward Crystal Reservoir. It is uncertain whether the outflow from the restored Bradford Springs will reach the reservoir, but if so, it could create problems with dewatering Crystal Reservoir for dam removal.

Funding and other factors may affect the order in which projects are implemented in the CMU.

Alternative sequences for CMU restoration projects are feasible but would require minor changes to the dewatering and construction plans listed in this document.

1.2 Permitting

Permitting should be initiated early in the project planning process to ensure that there are no permitting-related delays to project schedules. The contractor should work with the Fish and Wildlife Service (FWS) to determine who will be responsible for acquiring which permit.

Permits that may be required for CMU restoration projects include:

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NEPA – Required for all federally funded projects.

o Endangered Species Act and State Historic Preservation Act Consultations – often required as part of NEPA.

ACOE 404 Permit – Required for any project that involves work in the waters of the United States.

NDEP 401 Water Quality Certification – Required for any construction project that involves work in waters within the State of Nevada.

NDEP Working in Waterways – Required for any project that involves placing soil or gravel fill material into a water body.

NDEP Construction Stormwater – required for any construction project greater than 1 acre in area that can potentially result in stormwater reaching a waterway.

OBEC recommends that AHME consult with permitting authorities to determine whether permits for multiple projects in the Crystal Spring Management Unit can be obtained simultaneously.

1.3 Budgeting for Restoration Projects

When restoring disturbed environments, OBEC believes that revegetation and follow-up maintenance may be as important to overall project success as the initial earthmoving activity.

Cattails and other weeds establish quickly around recently restored spring pools and channels.

To control undesirable species, and especially during the first few years after restoration, OBEC recommends intensive revegetation with native plants and proper follow-up maintenance and weed treatments. OBEC also strongly recommends that restoration projects be implemented only after sufficient funding and labor have been obtained to support revegetation and maintenance of each project site.

2 HYDROLOGIC BARRIERS

Hydrologic barriers to water flow, such as ditches and berms, have been numbered for easy reference in the following construction sequencing discussion. Figures depicting all labeled hydrologic barriers referred to in this report are provided in a separate report, the Ash Meadows Biophysical Assessment and Restoration Plan: Upper Carson Slough and Crystal Spring Management Units, Appendix B – Hydrologic Barriers of the Crystal Spring Management Unit (Otis Bay, Inc., 2012a).

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3 CONSTRUCTION SEQUENCES FOR PROPOSED CMU RESTORATION PROJECTS

3.1 Crystal Spring

Crystal Spring is located approximately 0.5 miles east of Refuge headquarters and flows west through a portion of channel which was restored in 1996. This upper channel section contains some wide, slack water areas that encourage undesirable cattail overgrowth. Further restoration actions to narrow the channel may be considered to control this problem.

Approximately 2,300 ft downstream from the springhead, the restored portion of channel ends and Crystal Spring’s outflow enters a series of concrete ditches. One ditch carries water south toward Crystal Reservoir; the others flow west and then south to Horseshoe and Lower Crystal Reservoirs. Below Lower Crystal Reservoir, the Crystal drainage converges with that of the Point of Rocks Springs, Jackrabbit and Big Springs, and eventually with the Carson Slough drainage.

3.1.1 Construction Timing

For reasons discussed in Section 1.1, Recommended Sequence of Restoration Projects, OBEC recommends that restoration construction activities associated with Crystal Spring occur before restoration of Crystal Reservoir and the other springs of the CMU. OBEC recommends that construction occur during drier months (spring or fall) so that machinery may operate under the driest possible conditions. Constructing during times of summer monsoonal rains (August) or winter precipitation (Jan-March) may create less desirable conditions for operation of machinery.

3.1.2 Pre-Construction

3.1.2.1 Pre-job Conference

The implementing contractor and FWS should hold a pre-job conference to coordinate between stakeholders, state and federal agencies, and other interested parties. The meeting will be used to review the construction sequence and schedule, highlight Refuge issues and concerns, explain procedures to avoid unnecessary impacts, delineate procedures to follow Best Management Practices (BMPs), and present expected final conditions. The pre-job conference will allow stakeholders to understand the work sequence, express concerns, and request modifications to the implementation plan.

3.1.2.2 Clear or Cut Emergent Vegetation within Restoration Footprint

Aggressively colonizing vegetation (native or non-native), such as cattail and common reed, must be cleared, cut and maintained to give desirable emergent vegetation a competitive edge in colonization and occupation. OBEC recommends that manual cutting of cattails and common reed from within the project area be completed during the July prior to project implementation, as recommended in the Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge (U.S. Fish and Wildlife Service, 2006). Cuttings and removal of cut stems during this time will deplete plants’ food resources and hinder growth. In all marsh or

Page 4 Crystal Spring Management Unit Construction Sequence low gradient channel areas, intensive cattail and common reed management along with native revegetation efforts before and after construction should curb overgrowth of undesirable plants while facilitating the establishment of desirable native sedges and rushes over time.

3.1.2.3 Construction Staking

The contractor should stake, flag, and fence all cut/fill areas, staging areas, areas that should be protected from disturbance, and locations of rare plants and archaeological sites. Currently, rare plants and archaeological sites do not occur in the proposed restored channel footprint;

however, some archaeological sites occur along ditches that would be removed during the lower Crystal Spring channel restoration, and rare plants occur along the existing upper Crystal Spring channel. Construction staking should include establishing and marking the area and dimensions of the restored lower Crystal Spring outflow channel. Staking may also be used to delineate ditches that may need to be removed prior to outflow construction. Refuge staff should agree to design plans and alignments after a site visit and prior to construction implementation.

3.1.2.4 Mobilization and Construction Access

Heavy equipment should be pressure-washed prior to arrival at the work site to remove weeds and contaminants. Following arrival of heavy equipment, haul roads and staging areas can be graded as needed. Materials and supplies can be transported to the work site and stockpiled in the staging area. The Refuge Headquarters and maintenance yard, due to its proximity to Crystal Spring, may provide an appropriate staging area for construction equipment and materials. Construction access roads and staging areas are shown in Figure 1. Access to the channel construction area will be via the existing Spring Meadows and Horseshoe Marsh Loop Roads. During construction of the channel, the channel footprint and deconstructed ditches may be used as access roads to minimize disturbance to natural areas.

3.1.2.5 Install Fish Barrier and Remove Non-Native Species

A fish barrier may be installed in the upper Crystal Spring channel to prevent future passage of non-native centrarchid fish (such as green sunfish) to the upper Crystal Spring pool and stream.

Once the fish barrier is in place, the pool and stream above the barrier should be surveyed for non-native fish, and non-native fish should be removed from the upper stream and pool.

If a fish barrier is installed in the upper Crystal Spring channel and non-native species removal efforts above the barrier are successful, then thoroughly dewatering and drying the lower project area (as described in section 3.1.2.6) may successfully eradicate centrarchid fish from the entire Crystal Spring channel area. Centrarchid fish would then be constrained to Crystal, Lower Crystal, and Horseshoe Reservoirs. Subsequent fish barrier construction and drying of artificial impoundments after lower Crystal Spring outflow channel restoration has been completed would potentially allow AHME to eradicate unwanted centrarchid fish from the Crystal Spring system.

Figure 1. Construction access, staging areas, and proposed restoration features for lower Crystal Spring.

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3.1.2.6 Dewater the Project Site

Dewatering the work site should begin a minimum of one month before channel excavation to allow the project area adequate time to dry before construction begins. During construction of the lower Crystal Spring channel, all water from Crystal Spring can be sent down existing ditch #22 to Crystal Reservoir, as shown in Figure 1.

3.1.3 Construction

3.1.3.1 Removal of Ditches

All ditches and berms in the lower Crystal Spring drainage area, except for ditch #22 (dewatering channel) and ditch #9 (which will remain in place after restoration to carry water to Lower Crystal Reservoir, as shown in Figure 1) may be removed or filled at this time, creating a level surface for channel construction. Stalks of cattails and common reed removed from the channel construction footprint (as described in Section 3.1.2.2) may be buried in the old ditches as they are filled in.

3.1.3.2 Modify Upper Crystal and Excavate the Lower Crystal Spring Channel

The upper Crystal Spring channel may be narrowed to create faster flowing sections that may better inhibit unwanted cattail growth. The single-thread section of the lower Crystal Spring outflow channel should be excavated to match dimensions of the upper Crystal Spring outflow channel. A 10-foot wide earthen plug should be left at the upstream end of the restored channel to prevent water from Crystal Spring from entering the restored channel until restoration is complete. As the channel begins to branch into an anastomosing pattern, the channels can be made smaller, eventually becoming shallow scrapes that will guide water into the marsh toward the west. Excavation of the lower channel will occur under dry conditions.

3.1.3.3 Add Substrate for Aquatic Habitat

Gravel and sand substrate may be added to portions of the channel to set hydraulic grade and provide aquatic habitat (riffles, pools and runs) for fish, invertebrates, and benthic organisms.

Gravel that best meets habitat suitability requirements should be selected from local sources.

A gravel mix ranging in size from sand to 1.5” gravel rounds is recommended.

3.1.3.4 Extend Crystal Marsh North of Spring Meadows Road

OBEC recommends that Crystal Marsh be expanded to include an area north of Spring Meadows Road, as shown in Figure 1. These recommendations are based on existing topography and historical records, as explained in the Ash Meadows Biophysical Assessment and Restoration Plan (Otis Bay, Inc., 2012a). Currently, a wetland does not exist north of Spring Meadows Road, but Refuge managers can verify the existence of a historical marsh by taking soil core samples from this area for analysis, as performed in Palacios-Fest’s study (2006).

Because rare native plant species such as the Amargosa niterwort already occur in the vicinity

Page 8 Crystal Spring Management Unit Construction Sequence of Horseshoe and Lower Crystal Reservoirs, careful analysis of habitat enhancement priorities should be made to determine where wetland habitat enhancement is desired before implementing final Crystal Spring restoration measures. OBEC recommends restoration of a marsh north of Spring Meadows Road, along with the restoration of natural marsh areas in the vicinity of Horseshoe and Lower Crystal Reservoirs to expand shallow water habitat for a suite of native wildlife and plant species in AHME. To extend the marsh north of Spring Meadows Road, the following steps would be required:

Restore Dunes A line of dunes that was breached in four locations (along Ash Meadows Road and three smaller ditches located north of the road) should be patched, so that the dunes may again act as a natural water boundary along the west side of the marsh wetland. Heavy machinery, including excavators, dozers, and dump trucks (see heavy equipment recommendations in Section 0), can be used to move dune material to patch or fill breaches in the dunes that would otherwise permit water passage.

Raise Spring Meadows Road To accommodate for the increased water level in the marsh at the end of the lower Crystal Spring channel, approximately 800 ft of Spring Meadows Road extending eastward from the dunes should be raised approximately 1-3 feet. The goal of raising the road will be to obtain a consistent height of two feet above water surface, thus amount of road fill will vary based on location and water depth (e.g., low road fill at shallow end, highest road fill at deep end). A series of oversized box-culverts (shown in Figure 1) should be installed to allow water passage under the road and to prevent water damage to the road itself.

*NOTE: If AHME does not wish to extend the marsh north of Ash Meadows Road, the road will still need to be raised and the dunes altered to accommodate for increased water level in the marsh that will form at the end of the restored Crystal Spring channel.

3.1.3.5 Modify Existing Ditch #9

At the end of the anastomosing channel area, OBEC recommends that water from Crystal Spring be allowed to flow both north (as described in section 3.1.3.4) and south through existing ditch #9 (as shown in Figure 1). Currently the elevation at ditch #9 is about one foot higher than the elevation of the land north of the remnant anastomosing channel section. The bottom grade of ditch #9 should be lowered one foot to match an elevation of 2,162 ft.

Lowering the bottom elevation of ditch #9 would encourage water to flow south, toward Lower Crystal Reservoir and an area of rare plants, as well as north.

3.1.3.6 Install Water Control Structure (Optional)

A water control structure may be installed at the upstream end of ditch #9 and used by Refuge managers to control the direction of water flow. When the gate is closed, water would only flow north, and this diversion could be used as a management tool if drying up the lower

Otis Bay, Inc. Page 9 reservoirs to eradicate centrarchid fish. When the gate at ditch #9 is opened, water would flow both north and south.

3.1.3.7 Remove Horseshoe and Lower Crystal Reservoirs (Optional)

Removal or breaching of berms that impound water in Horseshoe and Lower Crystal Reservoirs may be completed to restore these areas to natural shallow marshes that are less likely to harbor bass or larger game fish. Removal of these berms would likely facilitate drainage of the lower reservoirs if these reservoirs are drained to remove centrarchid fish.

3.1.3.8 Introduce Flows

When channel construction is complete, water from Crystal Spring can be re-routed from the dewatering ditch into the new channel. An excavator will be used to connect the two channels, and soil fill material can be placed into the dewatering ditch to prevent water from traveling toward Crystal Reservoir.

3.1.3.9 Remove Dewatering Ditch

The dewatering ditch (Ditch #22) leading from the upper Crystal Spring channel to Crystal Reservoir can be removed. Removing the source of water from Crystal Reservoir will begin the dewatering process for removal of the Crystal Reservoir Dam, as described in a separate report, the Crystal Reservoir Rehabilitation Plan (Otis Bay, Inc., 2012b).

3.1.4 Post-Construction

3.1.4.1 Site Cleanup

Any leftover construction material will be removed from the site and disposed of or stockpiled in an appropriate area. BMPs such as fencing or flagging used to protect site features should be taken down and disposed of or stockpiled in an appropriate area.

3.1.4.2 Revegetation

Emergent marshes vital to these recommended restoration plans will likely be colonized by Typha (cattail) and Phragmites (common reed), which have become weedy in recent decades.

Although cattails and common reed are native to AHME, they may contain non-native genotypes that allow them to spread and outcompete native plants (Larkin et al., 2012;

Saltonstall, 2002). Endemic fish species of concern do not utilize clogged cattail or common reed-dominated channels but can persist in native bulrush and sedge communities that allow open flowing water (Baldino, C., pers. comm. 2012). Therefore, efforts to restore anastomosing channels and associated marshes must include planning to discourage Typha and Phragmites colonization and funds for monitoring and prompt treatment of infestations. Creation of shallow standing water without immediate revegetation efforts is strongly discouraged.

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The area within the construction footprint should be revegetated with native plants by the USFWS. Mulch, containerized plants, wetland plugs, seed and irrigation may be necessary to reestablish native vegetation. Intensive revegetation efforts will be critical to prevent invasive species from taking over bare and disturbed soils. The Upper Carson Slough and Crystal Spring Management Units Final Revegetation Plan (Otis Bay Ecological Consultants, 2012) identifies weeds requiring management in the Crystal Spring, Horseshoe, and Lower Crystal Reservoir areas. This same report provides native plant selection suggestions for replacement revegetation.

3.1.4.3 Weed Management

Channels in low-gradient, low water velocity areas will need periodic maintenance to control overgrowth of emergent vegetation, such as cattails or common reed, which could clog channel passages to water flow. Habitat restoration goals aim toward the re-establishment of open channels lined with native sedges. However, if weedy cattails or common reed, historically uncommon in the area, start to dominate and clog shallow channel areas, management action will be needed. Control methods that include treatment timing recommendations, and methods such as manual cutting, solarization, and herbicide treatment compatible for use in areas with aquatic organisms, are discussed in detail in the Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge (U.S. Fish and Wildlife Service, 2006).

3.1.4.4 Salvage and Transfer Native Fish

AHME biologists may wish to trap and move native aquatic organisms such as the Ash Meadows Amargosa pupfish from Lower Crystal Reservoir to the restored Crystal Spring. If Horseshoe and Lower Crystal Reservoirs are to be desiccated to remove non-native centrarchid fish from this system, then native fish or other aquatic organisms in this area will temporarily lose aquatic habitat. To preserve local genetics, native fish and invertebrates in the areas to be desiccated may be salvaged and moved above the water diversion gate at ditch #9.

3.2 Crystal Reservoir

OBEC recommends that the removal of Crystal Reservoir and Dam occur after the restoration of Crystal Spring channel, as described in Section 1.1 of this document. Construction plans and construction sequence for Crystal Reservoir are located in a separate document, the Crystal Reservoir Rehabilitation Plan and Construction Sequence (Otis Bay, Inc., 2012b).

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Figure 2. Construction access, staging areas, and proposed restoration channels for Kings, Forest, and Davis Springs.

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3.3 Lower Kings Spring Outflow Channel

Kings Spring is located approximately 4.5 miles from Refuge headquarters, at the end of Point of Rocks Road. The upper 2,400 feet of the historical Kings Spring outflow channel was reconstructed during 1997-98. Today, water from Kings Spring flows down the section of restored channel and into ditch #54, which carries water west toward Lower Crystal Reservoir.

A proposed restoration design for the lower portion of Kings Spring outflow channel (an additional 6,175 feet of channel) is described in the Ash Meadows Biophysical Assessment and Restoration Plan (Otis Bay, Inc., 2012a). This construction sequence contains plans for construction of the proposed restoration design and removal of ditches and berms that act as barriers to natural hydrology in the Kings Spring drainage area. Figure 2 shows construction access roads, staging areas, and the proposed alignment for the lower Kings Spring outflow channel.

3.3.1 Construction Timing

OBEC recommends that the lower Kings Spring channel be restored after Crystal Spring channel and Crystal Reservoir, and before Forest, Davis, Bradford and Tubbs Springs, as described in Section 1.1, Recommended Sequence of Restoration Projects. Channel construction on the lower portion of the Kings Spring outflow channel will occur in a dry upland area (all outflow from the upper Kings Spring channel currently flows west in a ditch). Construction on this channel segment may occur at any time of year; however, constructing during times of summer monsoonal rains (August) or winter precipitation (Jan-March) may create less desirable conditions for operation of machinery.

3.3.2 Pre-Construction

3.3.2.1 Pre-Job Conference

The implementing contractor and FWS should hold a pre-job conference to coordinate between stakeholders, state and federal agencies, and other interested parties. The meeting will be used to review the project implementation and construction sequence, highlight Refuge issues and concerns, explain procedures to avoid unnecessary impacts, delineate procedures to follow BMPs, and present expected final conditions. The pre-job conference will allow stakeholders to understand the work sequence, express concerns, and request modifications to the implementation plan.

3.3.2.2 Collect and Move Native Aquatic Organisms

Lower Kings Spring channel will be constructed in a dry upland area, so it will be unnecessary to collect and move native aquatic organisms from the site prior to channel construction.

Prior to moving water into the new channel, however, it may be necessary to move aquatic organisms from the ditch (ditch #54) that currently receives the outflow from the upper Kings Spring channel. Scoppettone et al. (2012) recorded rare occurrences of Ash Meadows Amargosa pupfish in this ditch. Before moving water into the restored channel (thus removing

Page 14 Crystal Spring Management Unit Construction Sequence a major source of water from ditch #54), AHME biologists may wish to trap and move sensitive wildlife such as Ash Meadows Amargosa pupfish from the ditch.

3.3.2.3 Construction Staking

Prior to mobilization, the contractor should stake, flag, and/or fence the channel alignment, other cut/fill areas, access roads and staging areas. The contractor (under direction of AHME staff) should also flag or fence areas that should be protected from disturbance, such as locations of rare plants and archaeological sites. A large patch of Ash Meadows gumplant is located at the downstream end of the lower Kings Spring channel, and three archaeological sites are located in close proximity to the upper end of the proposed channel. Construction staking should include establishing and marking grades along the length of the proposed channel. Refuge staff should agree to design plans and alignments after a site visit and prior to construction implementation.

3.3.2.4 Mobilization and Construction Access

and contaminants. Following arrival of heavy equipment, haul roads and staging areas can be graded as needed. Materials and supplies can be transported to the work site and stockpiled in the staging area.

A construction access map is shown in Figure 2. Access to the northeastern portions of channel will be via a dirt road from the direction of Point of Rocks Road. Access to lower portions of the channel construction area will be via the existing Ash Meadows Road. During construction of middle portions of the channel, the channel footprint can be used as an access road, minimizing disturbance to natural areas. A small equipment staging area will be located toward the southwest end of the channel, close to where the lower Kings Spring channel crosses Ash Meadows Road. A second staging area will be located near Forest Spring.

3.3.2.5 Dewatering the Project Site

During construction of the restored lower Kings Spring channel, the outflow from Kings Spring will remain in the existing outflow ditch (#54), so dewatering the project area will not be necessary. Construction of the lower Kings Spring channel will occur in a dry area.

3.3.3 Construction

3.3.3.1 Clear Existing Vegetation

Overgrown vegetation may be mechanically cleared from the channel construction footprint using an excavator or skidsteer. At this time, invasive species such as common reed (Phragmites) that are present within the construction zone can be mechanically removed, and re-sprouts can be re-treated with herbicide. In accordance with the Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge (U.S. Fish and Wildlife Service, Otis Bay, Inc. Page 15

2006), existing common reed in ditch #54 may be cut in July to remove flowers prior to seeding, thereby assisting with control and preventing spread of this plant prior to construction. If construction activities do not occur in July, then common reed stands may need to be manually cut in July before restoration begins.

3.3.3.2 Reconstruct Historic Channel

The contractor should reconstruct the lower Kings Spring channel in three segments (as shown in Figure 2): 1) the segment located south of Ash Meadows Road; 2) the segment located between Ash Meadows Road and ditch #54; and, 3) the segment located north of ditch #54.

Construction of channel segments should progress from the southwestern segment (#1) to the middle segment (#2) to the northeastern segment (#3). The final step will be to connect the three portions of reconstructed channel to the existing Kings Spring outflow channel, thus introducing water.

The proposed channel alignment follows the alignment of the historical channel, portions of which may still be intact. The channel will be reconstructed by cleaning and clearing debris and vegetation, or excavating (as necessary) a naturally shaped, meandering outflow channel into the location of the historical drainage. The upper Kings Spring outflow channel was constructed as a U-shaped channel, approximately 3.5 feet wide at the water surface and 1.5 feet deep.

The lower Kings Spring outflow channel should be constructed using a small excavator, to match and blend with the dimensions of the previously restored upper channel.

Segment 1: South of Ash Meadows Road Approximately 1,350 feet of channel will be restored south of Ash Meadows road. Work should begin at the edge of a patch of rare plants (Ash Meadows gumplant, to be flagged or fenced off during construction staking, as described in Section 3.3.2.3). Beginning at the far downstream end of the channel, work will progress upstream toward Ash Meadows Road using the channel footprint as an access road to minimize disturbance to surrounding vegetation. Excess soil fill material generated by channel excavation may be stockpiled and used to fill existing ditches (see section 3.3.3.7) or spread to blend with natural topography.

Segment 2: Between Ash Meadows Road and Ditch #54 Channel reconstruction may begin at Ash Meadows Road and move upstream or begin at Ditch 54 and work downstream. Work will be done under dry conditions, so construction may begin at the upstream or downstream end of the channel, depending on contractor preference.

During reconstruction of middle portions of the channel, the channel footprint should be used as an access road to minimize disturbance to the surrounding area.

Segment #2 of the lower Kings Spring channel (approximately 3,700 feet in length) extends from the north side of Ash Meadows road to approximately 10 feet south of ditch #54. By leaving a 10-foot gap between the lower Kings Spring channel and ditch #54, water will be prevented from flowing into the new channel until construction is complete. Excess soil fill

Page 16 Crystal Spring Management Unit Construction Sequence material generated by channel excavation can be stockpiled and used to fill ditches (see section 3.3.3.7) or spread and graded to blend with natural topography.

Segment 3 (North of Ditch #54) The final step in the excavation of lower Kings Spring channel will be to construct the northeastern segment, approximately 900 feet in length. Construction should stop approximately 10 feet short of the existing (previously restored) upper Kings Spring channel. A 10-foot gap in channel construction will prevent water from flowing into the new channel until construction is complete.

3.3.3.3 Install Culverts at Road Crossing

An oversized box culvert that is appropriately-sized to handle large floods should be installed between channel segments 1 and 2 and set to the appropriate grade to allow for water passage under Ash Meadows Road. A second culvert may be required further downstream where the historic drainage would lead water across Spring Meadows Road. Dimensions of the culverts need to be determined prior to restoration implementation.

3.3.3.4 Add Substrate for Aquatic Habitat

Gravel/sand substrate may be added to portions of the channel to set hydraulic grade and provide aquatic habitat (riffles, pools and runs) for fish, invertebrates, and benthic organisms.

3.3.3.5 Trap and Move Native Aquatic Organisms from Ditch #54.

AHME biologists may wish to trap and move native aquatic organisms such as Amargosa pupfish from ditch #54 prior to the introduction of flows into the reconstructed channel. After moving the Kings Spring outflow into the restored channel, the major source of water carried by ditch #54 will have been removed.

3.3.3.6 Introduce Flows

After channel construction is complete and the channel is ready for water, the 10-foot wide soil plug that remains between Segment 2 and ditch #54 can be removed using an excavator, and water can be introduced into Segments 2 and 1. The excavator can then work its way upstream, removing the soil plug between ditch #54 and Segment 3. Finally, the excavator can remove the soil plug between Segment 3 and the previously restored upper Kings Spring channel, releasing water into the entirety of the new channel from the northeastern end. Soil left over from channel excavation can be used to create a soil plug at the entrance of ditch #54 and the other abandoned channel segment, blocking water from traveling down the main ditch toward Forest and Tubbs Springs.

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3.3.3.7 Remove Existing Berms and Ditches

Remaining berms and ditches that fall within the construction area and act as barriers to natural drainage patterns in the Kings Spring Outflow region can be removed at this time, including the portion of ditch #54 that leads toward Forest, Davis, Tubbs and Bradford Springs.

Along many ditches at AHME, excavated soil was stockpiled, forming berms. Additional soil fill material will be generated during construction of the outflow channel. Using these soil sources, the contractor will partially or fully remove and/or plug these ditches, and the area will be finish-graded to match natural topography. Ideally, the barriers should be removed completely from the landscape; however, depending on available funding and other factors, AHME may choose to remove only the portions of these berms and ditches that most directly affect hydrologic processes.

3.3.3.8 Finished-grading and Soil Decompaction

All compacted and disturbed soils should be ripped, raked and graded, including access roads and stockpile areas, to promote vegetation recovery.

3.3.4 Post-Construction

3.3.4.1 Site Cleanup

Leftover construction material will be removed from the site and disposed of or stockpiled in an appropriate area. BMPs such as fencing or flagging used to protect site features should be

3.3.4.2 Revegetation

Following construction, the area within the construction footprint should be revegetated with native plants by the USFWS. Mulch, containerized plants, wetland plugs, seed and irrigation may be necessary to reestablish native vegetation. Intensive revegetation efforts will be critical to prevent invasive species from taking over bare soils.

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3.4 Forest Spring

3.4.1 Construction Timing

OBEC recommends that Forest Spring restoration occur after completion of the lower King Spring restored outflow channel, because water from the restored Forest Spring channel will flow directly into the restored lower Kings Spring channel. Coordination of restoration projects in this order is important for dewatering and outflow ditch removal logistics, as discussed in Section 1.1. Construction during spring or fall is recommended to avoid summer and winter precipitation events that could interfere with construction equipment operation.

3.4.2 Pre-Construction

3.4.2.1 Pre-job Conference

The implementing contractor and FWS should hold a pre-job conference to coordinate between stakeholders, state and federal agencies, and other interested parties. The meeting will be used to review the project implementation and construction sequence, highlight Refuge issues and concerns, explain procedures to avoid unnecessary impacts, delineate procedures to follow BMPs, and present expected final conditions. The pre-job conference will allow stakeholders to

3.4.2.2 Construction Staking

The contractor should stake, flag, and fence the cut/fill areas, staging areas, areas that should be protected from disturbance, and locations of archaeological sites. Areas containing rare plants do not currently occur within the construction footprint, thus should not be a concern for Forest Spring restoration activity. An archaeological site located approximately 90 feet west of the spring pool should be flagged and/or fenced for protection. Construction staking should include establishing and marking the area and dimensions of the restored Forest Spring outflow channel. Staking may also be used to delineate areas around the banks of Forest Spring that may need to be re-graded prior to outflow construction. Refuge staff should agree to design plans and alignments after a site visit and prior to construction implementation.

3.4.2.3 Pre-construction, Mobilization, and Construction Access and contaminants. Following arrival of heavy equipment, haul roads and staging areas can be graded as needed. Materials and supplies can be transported to the work site and stockpiled in the staging area. Access to Forest Spring may occur via an abandoned dirt road that leads south from Point of Rocks Road. Wetland pads or mats may be used if construction machinery will be working in wet areas. To keep disturbance of natural areas to a minimum, a staging area for equipment and any raw material used for channel construction may be located in an old agricultural field along the access road to Forest Spring (Figure 2).

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3.4.2.4 Clear Existing Vegetation

Overgrown vegetation may be mechanically cleared from the construction access road, spring pool outflow area, and construction footprint as needed. Every effort should be made to keep unnecessary disturbance to a minimum, and native vegetation should be salvaged for revegetation efforts if possible. In accordance with the Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge (U.S. Fish and Wildlife Service, 2006), existing common reed may be cut in July to remove flowers prior to seeding and assist with controlling and preventing spread of this plant prior to construction on the Forest Spring channel. If channel construction at Forest Spring occurs later than July, then common reed stands may need to be manually cut in July before restoration begins.

3.4.2.5 Dewatering the Project Site

To dewater the project site, the existing outflow channel can be connected with the restored lower Kings Spring channel via a short (40 ft) section of constructed channel (shown in Figure 2). Repairing the existing outflow ditch may be necessary in order to contain the outflow in a better-defined channel. This action will allow construction of the restored Forest Spring channel in dry conditions.

3.4.3 Construction

3.4.3.1 Channel Construction

Because construction of Forest Spring channel will occur under dry conditions, channel excavation may begin at the upstream or downstream end, depending on contractor preference. A 10-foot wide earthen plug should be left at the top end of the restored channel to prevent water flow from Forest Spring from entering the restored channel until restoration is complete. The channel footprint can be used as an access road during channel construction to limit disturbance to the surrounding area.

Approximately 475 feet of channel will be constructed between Forest Spring and lower Kings Channel. Forest Spring is believed to produce little outflow, and OBEC recommends that the channel can be constructed as a simple v-shaped drainageway using an excavator with a small bucket. Soil material excavated during channel construction can be stockpiled for use in filling ditches, or spread to match surrounding topography. Outflow channel construction at Forest Spring will also entail some re-grading of the banks surrounding the spring pond to create an appropriate outlet orientation aligned with the new outlet channel.

3.4.3.2 Re-size Spring Pool

Forest Spring pool has been mechanically enlarged in the past, and OBEC recommends decreasing the pool to a more natural size. If accurate discharge measurements can be obtained after overgrown vegetation is cleared from the outflow ditch, appropriate pool dimensions can be developed. The spring sediment study (section 5.2 of OBEC’s 2012 Ash Meadows Biophysical Assessment and Restoration Plan) can be referenced for more

Page 20 Crystal Spring Management Unit Construction Sequence information. Caliche slabs and other native materials can be used to decrease the size of Forest Spring pool and improve aquatic habitat for native wildlife.

3.4.3.3 Add Substrate for Aquatic Habitat

Gravel/sand substrate may be added to portions of the channel to set hydraulic grade and provide aquatic habitat (riffles, pools and runs) for fish, invertebrates, and benthic organisms.

3.4.3.4 Introduce Flows into the New Channel

Once channel construction is complete, an excavator may be used to remove the earthen plug between the restored Forest Spring channel and Kings Spring channel. The earthen plug at the new Forest Spring outlet may then also be removed to allow water to spill into the new channel.

3.4.3.5 Remove Ditches

Once water is turned into the restored Forest Spring outflow channel, the old ditch connecting Forest Spring to ditch #54 may be filled in. The downstream portion of ditch #54 that occurs below Forest Spring and heads toward Bradford and Tubbs Springs may also be removed at this time. Along many ditches, excavated soil was stockpiled, forming berms. The contractor may take soil from the berms to fully or partially remove and/or plug ditch #54. Any other berms and ditches in this area may be removed or filled in at this time.

3.4.3.6 Finished-grading and Soil Decompaction

The bank area along the newly constructed Forest Spring pool and outflow channel will be finish-graded to match natural topography. All compacted and disturbed soils should be ripped, raked and graded, including access roads and stockpile areas to create loose soil conditions that can support natural or manual re-seeding and promote vegetation recovery.

3.4.4 Post-Construction

3.4.4.1 Site Cleanup

Any leftover construction material will be removed from the site and disposed of or stockpiled in an appropriate area. BMPs such as fencing, wetland pads, or flagging used to protect site features should be taken down and disposed of or stockpiled in an appropriate area.

3.4.4.2 Revegetation

native plants by the USFWS. Suggested plant species for native vegetation recovery are

Otis Bay, Inc. Page 21 presented in the Upper Carson Slough and Crystal Spring Management Units Final Revegetation Plan (Otis Bay Ecological Consultants, 2012). Mulch, containerized plants, wetland plugs, seed and irrigation may be necessary to reestablish native vegetation. Intensive revegetation efforts will be critical to prevent invasive species from taking over bare soils.

3.4.4.3 Ash Meadows Speckled Dace Re-introduction

The Ash Meadows speckled dace was once part of the historical fish community in Forest Spring (Miller, 1948). This fish no longer occurs in either Forest Spring or in lower Kings Spring (Scoppettone et al., 2012). The cooler waters of Forest Spring, along with stream habitat restoration, could provide potential habitat that is suitable for speckled dace survival. Re-introductions of this fish into the system may be considered if deemed appropriate by Refuge biologists. Ash Meadows Amargosa pupfish may migrate to Forest Spring naturally from the connected Kings Spring outflow channel.

Page 22 Crystal Spring Management Unit Construction Sequence

3.5 Davis Spring

3.5.1 Construction Timing

Davis Spring restoration should occur after Forest Spring but before Tubbs Spring restoration to continue removal of ditch #54 in a downstream direction. As with other spring restoration efforts, construction during the spring or fall months is recommended to avoid winter and summer precipitation events that could interfere with construction equipment operation.

3.5.2 Pre-Construction

3.5.2.1 Field Measurements

Davis Spring currently has no apparent outflow. Low discharge data coupled with historical aerial interpretation suggest that this spring would not likely provide a substantial outflow channel; however, if a spring discharge measurement were collected prior to restoration, flow modeling and proper restored channel dimensions could be developed.

Because invertebrate data at this spring are lacking, Refuge biologists may consider conducting invertebrate surveys at this spring to confirm native invertebrate presence or absence prior to spring manipulation.

3.5.2.2 Pre-job Conference

Prior to equipment mobilization, the implementing contractor and FWS should hold a pre-job conference to coordinate between stakeholders, state and federal agencies, and other interested parties. The meeting will be used to review the project implementation and construction sequence, highlight Refuge issues and concerns, explain procedures to avoid unnecessary impacts, delineate procedures to follow BMPs, and present expected final conditions. The pre-job conference will allow stakeholders to understand the work sequence, express concerns, and request modifications to the implementation plan.

3.5.2.3 Construction Staking

The contractor should stake, flag, and fence the cut/fill areas, staging areas, areas that should be protected from disturbance, and locations of rare plants and archaeological sites.

Construction staking should include establishing and marking the area and dimensions of the restored Davis Spring pool and outflow channel. Staking may be used to delineate areas around the banks of Davis Spring that may need to be re-graded prior to outflow construction.

Refuge staff should agree to design plans and alignments after a site visit and prior to

3.5.2.4 Pre-construction, Mobilization, and Construction Access and contaminants. Following arrival of heavy equipment, haul roads and staging areas can be

Otis Bay, Inc. Page 23 graded as needed. Materials and supplies can be transported to the work site and stockpiled in the staging area. Recommended access roads are shown in Figure 2. Because Davis Spring currently has no outflow, the restored channel may be excavated in an upstream direction toward the spring source in dry soil conditions.

3.5.3 Construction

3.5.3.1 Clear Existing Vegetation

If necessary, overgrown vegetation may be mechanically cleared from the construction access roads (primarily abandoned ditches) and within the construction footprint. In accordance with the Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge (U.S. Fish and Wildlife Service, 2006), existing common reed in ditch #54 may be cut in July to remove flowers prior to seeding and assist with control and spread of this plant prior to construction. If construction activities do not occur in July, then common reed stands may need to be manually cut in July before restoration begins. Every effort should be made to keep unnecessary disturbance to a minimum, and native vegetation should be salvaged for revegetation efforts if possible.

3.5.3.2 Dewater Work Area

Dewatering the work area will not be necessary because the spring pool currently produces no outflow.

3.5.3.3 Construct Spring Channel

Davis Spring currently has no outflow channel, though a remnant channel occurs in the area (Dudley & Larson, 1976). It is possible that after removal of pipes and decreasing the spring pool size, the spring will produce a small amount of outflow that would flow down the channel.

The proposed alignment for the restored Davis Spring channel follows the alignment of the remnant channel. Portions of the channel may require excavation, and other portions of channel may only require clearing of debris and overgrown vegetation. An earthen plug between the spring pool and the outflow channel may be left in place until water is turned into the restored channel. Some earth grading may need to be completed around the spring pool to allow for an outlet.

3.5.3.4 Remove Pipe

Currently, no underwater connection between Davis Spring and ditch #54 is known to exist.

Although submerged pipes may exist, a dye test performed in 2008 (Weissenfluh, D., pers.

comm. 2012) exhibited no evidence of movement to the Kings/Forest outflow ditch (ditch #54).

One large (~14’ diameter) pipe on the ground surface should be removed from Davis Spring prior to restoration. Other (closed) pipes that may be currently submerged in Davis Spring may be buried with spring pool re-configuration.

Page 24 Crystal Spring Management Unit Construction Sequence

3.5.3.5 Re-size Spring Pool

Davis Spring was not surveyed in early fish surveys (Miller, 1948) or on previous springsnail surveys (Hershler & Sada, 1987). Current Refuge staff members postulate that Davis Spring may have been a seep that was dug out to create a water hole (Weissenfluh, D.